RATH: On his first full day in Cuba, Pope Francis today celebrated mass in Revolution Plaza before a crowd of tens of thousands. Later this evening, Francis spoke to Cuban youth. He said that young people must embrace their dreams and addressed both believers and nonbelievers. Here he via interpreter on the network EWTN. (SOUNDBITE OF SPEECH)

FRANCIS: (Through Interpreter) And to you, Cuban youth, even though you may think differently, even though you may have different points of view, I wish that you go together seeking hope, seeking the future and the nobility of the country.

RATH: Pope Francis also met today privately with former leader Fidel Castro. Earlier, I spoke with NPR's Sylvia Poggioli in Havana. And she said that the pope's meeting with Fidel Castro did not come as a great surprise.

SYLVIA POGGIOLI, BYLINE: No, not really. We had been told it would probably happen. And in fact, Pope Francis's predecessor, Benedict the 16th, had met with Fidel Castro when he visited Cuba in 2012, even though Fidel had already resigned due to ill health and handed over the power to his brother. The Vatican spokesman, Father Federico Lombardi, said there would be no photographs of the encounter, although at least one has already been tweeted. The meeting lasted 40 minutes at Fidel's home. The spokesman described it as very familiar, fraternal and friendly. He said that Fidel wanted to talk about big issues facing the world and humanity, including the pope's recent document on the environment. And the spokesman said that when he had met Benedict, Castro had peppered the pope with questions. Today, it was more of a conversation. They exchanged several books as gifts. And later, the pope's meeting with President Raul Castro took place at the Presidential Palace, but there was - there were no formal speeches.

RATH: Pope Francis played a key role as facilitator of the secret negotiations between the U.S. and Cuba that led to the restoration of diplomatic relations after more than 50 years. How was he welcomed by the Cuban people?

POGGIOLI: Oh, well, absolutely huge numbers of people - large numbers turned out yesterday lining the streets from the airport to the city to watch the pope ride by in his Pope Mobile. Tens of thousands were in Revolution Square this morning for the mass. In Latin America, many people see the restoration of these ties as the end of this region's version of the Cold War, the divisions between leftist pro-Castro regimes and the dictatorships than in years past were allied with the United States. I've heard this process referred to as Latin America's version of the fall of the Berlin Wall.

RATH: And of course, Pope Francis is also the first Latin-American pope. Can you talk about how that factors into this visit?

POGGIOLI: Well, it's a big factor. One of the concepts dear to Francis is the prospect that Latin-American countries can now be reunited in one big homeland. He calls it a patria grande with more egalitarian, economic and social system; a kind of third way between capitalism and communism. Now, while many Cuban dissidents and opponents of the Castro regime criticized the Cuban Catholic Church as too timid to stand up to the regime, it's not a secret that the Vatican is very wary of the possibility of a violent transition from a communist regime to a western-style free market society. So in this sense, Pope Francis and the Catholic Church want to continue to play a mediating role in the Cuban transition process.

RATH: Sylvia, quickly, what's next on the pope's schedule?

POGGIOLI: Oh, it's intense. Tomorrow, he flies to the Cuban town of Holguin, later in the day to the city of Santiago where he'll visit the sanctuary of the virgin of charity. And on Tuesday, he flies to Washington for another four days packed with events.

RATH: That NPR's Sylvia Poggioli in Havana. Sylvia, thank you so much.